A coolant system for an internal combustion engine includes a coolant overflow tank or expansion reservoir to hold contain coolant that has expanded during hot operation. It is common to fabricate such reservoirs from plastic. Some reservoirs are provided a sensor, such as a level sensor or a pressure sensor. The engine coolant system is pressurized and coolant temperature can vary from ambient temperature at cold start, which could be well below freezing, to about 100 degrees C. The structural characteristics of the plastic varies over such a temperature range.
Referring to FIG. 1, a reservoir 10 has a cap 12, an opening 14 that communicates with other portions of a coolant system, a mounting tab 16, a sensor 18 with the connector visible, and a sensor 20, which has a cord 22 extending from it with a connector 24. Sensors 18 and 20 may be pressure and fluid level sensors, as examples. When the plastic of reservoir 10 expands or contracts due to changes in temperature, a tensile or compressive force may be applied to the sensors. Such forces can negatively impact the sensor's output signal thereby reducing accuracy. One way to prevent such inaccuracies would be to increase the thickness of the material used in fabricating the reservoir or to use more expensive material that is tougher. However, this increases cost and weight of the reservoir. A sensor mount that prevents the distortion of the reservoir due to pressure and temperature variations to transmit forces confounding the signal is desired.